The present invention concerns a spraying device for fast microbiological analysis.
At present, checking the microbiological quality of liquids, gases or surfaces in the context of industrial and medical activities has to conform to strict standards.
On account of this, the industrial players and health authorities must have tools at their disposal making it possible to detect microbiological contaminations as soon as possible, in order to be able to correct these in good time and at reduced cost.
In practice, microbiological monitoring is carried out on a gel growth medium where microorganisms, after having been collected on a microporous membrane, are cultured until they have been rendered visible to the naked eye.
The incubation periods vary from one microorganism to another but are in general at least 24 hours and sometimes more for slower growth microorganisms (such as mycobacteria) or because the microorganisms have been stressed by environmental conditions.
To render the detection more rapid, another approach consists of reducing the minimum duration of culture (or even, for some microorganisms, of eliminating it completely) by basing the detection of the microorganisms on their metabolic activity.
A universal metabolic marker, most commonly adenosine triphosphate (ATP) contained in living microorganisms, is measured by bringing it into contact with a reagent revealing the presence of ATP by luminescence (termed a “bio luminescence reagent”) which enables the presence of microorganisms to be noticed without having to wait for colonies to form on a gel growth medium and to become visible to the naked eye.
The quantity of light emitted is a function of the mass of ATP and thus the number of microorganisms.
A device for detection by fast microbiology is already known which is commercialized by the applicant under the name Milliflex Rapid®, and which comprises:                a station for filtering a volume of liquid onto a membrane so as to capture the microorganisms that may be contained in the liquid on the membrane;        a station for spraying a reagent revealing the presence of ATP by luminescence facing which the operator places the membrane, after the filtering step and after having rendered the ATP of the microorganisms accessible (by a step of lysis of the microorganisms for example), for the reagent to be deposited; and        a station for measuring the quantity of light emitted in response to the depositing of the reagent revealing the presence of ATP by luminescence, facing which the operator places the membrane, after the spraying step, the light emitted by the membrane being collected by a CCD camera and processed and then analyzed to detect the presence of microorganisms on that membrane.        
The spraying station is provided with a spraying device comprising a sprayer spraying droplets emitted in the form of a jet onto the membrane in the ambient air situated above the membrane.